Circuit board device and its manufacturing method

ABSTRACT

This invention is a circuit board device having a filter element. It has a base board ( 4 ), a circuit part ( 2 ) mounted on the base board ( 4 ), a filter element ( 5 ) arranged between the circuit part ( 2 ) and the base board ( 4 ), and a semiconductor component ( 3 ) mounted on the same plate as the circuit part ( 2 ) on the base board ( 4 ). The semiconductor component ( 3 ) is mounted on a thin plate region ( 17 ) that is thinner than a thick plate region ( 16 ) having its thickness increased by mounting the circuit part ( 2 ) on the base board ( 4 ). Thus, the thickness of the whole circuit board device is reduced and the filter element ( 5 ) is covered with a sufficiently thick dielectric insulating material so as to prevent deterioration in filter characteristic.

TECHNICAL FIELD

[0001] This invention relates to a circuit board device having a filterelement and a method for manufacturing the same.

[0002] This application claims priority of Japanese Patent ApplicationNo.2001-380758, filed on Dec. 13, 2001, the entirety of which isincorporated by reference herein.

BACKGROUND ART

[0003] Recently, in high-frequency applications using a microwave bandor a milliwave band as a carrier, for example, in wireless LAN orvarious communication terminals, reduction in size and thickness ofequipment and circuit board has been demanded. In a circuit board forsuch high-frequency applications, filter elements such as a low-passfilter (LPF), a high-pass filter (HPF) and a band-pass filter (BPF) aredesigned with a distributed constant, for example, using a microstripline or a strip line that enables relatively high space-saving, insteadof using a lumped constant design using chip components like an inductorand a capacitor.

[0004] For example, a circuit board 100 shown in FIG. 1 has a BPF 101 ofa flat structure, as a filter element designed with a distributedconstant. In this circuit board 100, conductor patterns 103 made ofcopper or nickel plated with gold are formed as microstrip lines on adielectric board 102 such as a printed board or a ceramic board, thusconstituting the BPF 101. On the entire back side of the dielectricboard 102, a ground part (not shown) is formed.

[0005] With such a BPF 101, it is possible to selectively transmit asignal of a desired frequency band by optimizing the shape of theconductor patterns 103. Since this BPF 101 is a part of the wholepattern wiring formed on the dielectric board 102 and has a flatstructure, the BPF 101 can be collectively formed when forming thepattern wiring on the dielectric board 102, for example, by printprocessing, lithography processing or the like.

[0006] In the circuit board 100 shown in FIG. 1, since the BPF 101 has aflat structure and the conductor patterns 103 are arrayed with anoverlap of substantially ¼ of a passing wavelength λ, the length of theconductor patterns 103 is prescribed by the passing wavelength λ. In thecircuit board 100, the conductor patterns 103 need to have a certainlength and it is difficult to reduce the occupied area of the conductorpatterns 103. Therefore, area-saving is limited.

[0007] Thus, in a circuit board 110 shown in FIGS. 2A to 2D, it isproposed to save the area by using a BPF 111 as a filter element thatrequires a smaller occupied area. This BPF 111 has a so-called tri-platestructure, which is a three-layer structure in which resonator conductorpatterns 113 arranged substantially parallel to each other are formed inan inner layer of a multilayer board 112 such as a multilayer printedboard.

[0008] Specifically, in the BPF 111, feeder wirings 114 are connected tosubstantially central parts in the longitudinal direction of the tworesonator conductor patterns 113, as shown in FIG. 2C. The resonatorconductor patterns 113 are held between two ground parts 116 a, 116 b asground conductors, with dielectric layers 115 provided between theresonator conductor patterns 113 and the ground parts 116 a, 116 b, asshown in FIG. 2A. In this BPF 111, the two ground parts 116 a, 116 b areconnected with each other in the form of interlayer connection byvia-holes 117 and shield the resonator conductor patterns 113 in thelayer. In the BPF 111, each of the two resonator conductor patterns 113has a length that is substantially ¼ of the passing wavelength A,indicated by an arrow M in FIG. 2C. One end of each resonator conductorpattern 113 is connected to the via-hole 117 and the other end isopened. In this BPF 111, when shown in the form of an equivalent circuitas shown in FIG. 3, parallel resonance circuits are capacitive-coupled.Specifically, a parallel resonance circuit PR1 including a capacitor C1and an inductance L1 connected between one of the two resonatorconductor patterns 113 and the ground parts 116 a, 116 b, and a parallelresonance circuit PR2 including a capacitor C2 and an inductance L2connected between the other of the two resonator conductor patterns 113and the ground parts 116 a, 116 b, are capacitive-coupled via acapacitor C3.

[0009] Meanwhile, in the above-described circuit board 110, it ispossible to reduce the area of whole body by reducing the occupied areaof the filter element. However, when a semiconductor component 118 suchas an IC or a chip component is mounted on the major surface, as shownin FIG. 4, the thickness of the whole body indicated by an arrow t₁ inFIG. 4 is increased.

[0010] To solve this problem, it is proposed to reduce the thickness ofthe circuit board 110 indicated by an arrow t₂ in FIG. 5 and thus reducethe thickness of the whole body including the semiconductor component118, as shown in FIG. 5.

[0011] To realize the reduction in thickness of the semiconductorcomponent, the present applicant has proposed the techniques describedin the Japanese Publications of Laid-pen Patent ApplicationNos.2001-44704, 2001-44705 and 2001-44706. According to the techniquedescribed in these publications, if the thickness of the circuit board110 is reduced, that is, if the thickness of the dielectric board 115 isreduced, the degree of electromagnetic coupling between the resonatorconductor patterns 113 might not be sufficient, which affects thepassing characteristic at the time when an electric signal passesthrough the BPF 111. Therefore, in the circuit board 110 with thereduced thickness, the loss within the passband of the BPF 111 isincreased and the frequency bandwidth is reduced, making it difficult toacquire a desired filter characteristic.

DISCLOSURE OF THE INVENTION

[0012] It is an object of the present invention to provide a new circuitboard device and a method for manufacturing the same that enablesolution to the problem of the conventional circuit board device asdescribed above.

[0013] It is another object of the present invention to provide acircuit board device in which the thickness of its whole body is reducedwithout losing the filter characteristic of a filter element, and amethod for manufacturing the same.

[0014] A circuit board device according to the present inventionincludes: a base board having an insulating layer made of a dielectricinsulating material; a circuit part including a wiring layer and adielectric insulating layer and mounted on a major surface of the baseboard; a filter element arranged between the base board and the circuitpart; and a semiconductor component mounted on the same plane as thecircuit part mounted on the major surface of the base board; thesemiconductor component being mounted on a second region having athickness smaller than that of a first region having a large thicknessas the filter element is arranged between the base board and the circuitpart on the major surface of the base board.

[0015] In this circuit board device, since the semiconductor componentis mounted on the second region having a thickness smaller than that ofthe first region having a large thickness as the filter element isarranged between the base board and the circuit part on the majorsurface of the base board, the thickness of the whole body is small.

[0016] In the circuit board device, since the filter element is arrangedbetween the base board and the circuit part, that is, within the firstregion with a large thickness, and these base board and circuit parthave dielectric insulating layers, the filter element can be coveredwith the sufficiently thick dielectric insulating layers. As thedielectric insulating layers covering the filter element are madethinner, deterioration in filter characteristic is prevented.

[0017] A method for manufacturing a circuit board device according tothe present invention includes: a board forming step of forming a baseboard having an insulating layer made of a dielectric insulatingmaterial; a circuit part forming step of forming a circuit partincluding a wiring layer and a dielectric insulating layer; an elementforming step of forming a filter element on a major surface of the baseboard or a major surface of the circuit part; a circuit part mountingstep of mounting the circuit part on the major surface of the base boardso that the filter element is arranged between the base board and thecircuit part; and a semiconductor mounting step of mounting asemiconductor component on the same plane as the circuit part mounted onthe major surface of the base board; wherein at the semiconductormounting step, the semiconductor component is mounted on a second regionhaving a thickness smaller than that of a first region having a largethickness as the filter element is arranged between the base board andthe circuit part on the major surface of the base board.

[0018] In this method for manufacturing a circuit board device, sincethe semiconductor component is mounted on the second region having athickness smaller than that of the first region having a large thicknessas the filter element is arranged between the base board and the circuitpart on the major surface of the base board, a circuit board devicehaving a small thickness as a whole is manufactured.

[0019] In the method for manufacturing a circuit board device, since thefilter element is arranged between the base board and the circuit part,and these base board and circuit part have dielectric insulating layers,the filter element can be covered with the sufficiently thick dielectricinsulating layers. As the dielectric insulating layers covering thefilter element are made thinner, deterioration in filter characteristicis prevented.

[0020] The other object of the present invention and specific advantagesprovided by the present invention will be further clarified by thefollowing description of an embodiment referring to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a schematic plan view showing a circuit board having aband-pass filter of a flat structure.

[0022]FIGS. 2A to 2D show a circuit board having a band-pass filter of atri-plate structure. FIG. 2A is a partly perspective longitudinalsectional view of the circuit board. FIG. 2B is a plan view showing aground part of an upper layer. FIG. 2C is a plan view showing conductorpatterns. FIG. 2D is a plan view showing a ground part of a lower layer.

[0023]FIG. 3 is a circuit diagram showing the band-pass filter of thetri-plate structure in the form of an equivalent circuit.

[0024]FIG. 4 is a partly perspective longitudinal sectional view showinga conventional circuit board.

[0025]FIG. 5 is a partly perspective longitudinal sectional view showingthe state where the thickness is reduced in the conventional circuitboard.

[0026]FIG. 6 is a longitudinal sectional view showing a circuit boarddevice according to the present invention.

[0027]FIG. 7 is a partly perspective schematic plan view showing thecircuit board device.

[0028]FIG. 8 is a longitudinal sectional view for explaining a processof manufacturing the circuit board device, showing a dummy board.

[0029]FIG. 9 is a longitudinal sectional view for explaining the processof manufacturing the circuit board device, showing the state where afirst insulating layer is formed on the dummy board.

[0030]FIG. 10 is a longitudinal sectional view for explaining theprocess of manufacturing the circuit board device, showing the statewhere a wiring groove is formed in the first insulating layer.

[0031]FIG. 11 is a longitudinal sectional view for explaining theprocess of manufacturing the circuit board device, showing the statewhere a metal plating layer is formed on the first insulating layer.

[0032]FIG. 12 is a longitudinal sectional view for explaining theprocess of manufacturing the circuit board device, showing the statewhere a first wiring layer is formed.

[0033]FIG. 13 is a longitudinal sectional view for explaining theprocess of manufacturing the circuit board device, showing the statewhere a second insulating layer and a second wiring layer are formed.

[0034]FIG. 14 is a plane view of essential parts for explaining theprocess of manufacturing the circuit board device, showing a pair ofresonator conductor patterns exposed on a counter-surface.

[0035]FIG. 15 is a longitudinal sectional view for explaining theprocess of manufacturing the circuit board device, showing the statewhere a second shield part and a bump part are formed on the secondwiring layer.

[0036]FIG. 16 is a longitudinal sectional view for explaining theprocess of manufacturing the circuit board device, showing a circuitpart.

[0037]FIG. 17 is a longitudinal sectional view for explaining theprocess of manufacturing the circuit board device, showing a thick plateregion and a thin plate region provided by mounting the circuit part ona base board.

[0038]FIG. 18 is a longitudinal sectional view for explaining theprocess of manufacturing the circuit board device, showing the completedcircuit board device.

[0039]FIG. 19 is a longitudinal sectional view showing the state where athick semiconductor component and a thin semiconductor component aremounted in the circuit board device.

BEST MODE FOR CARRYING OUT THE INVENTION

[0040] An embodiment of the present invention will now be described indetail with reference to the drawings.

[0041] A circuit board device 1 to which the present invention isapplied, shown in FIGS. 6 and 7, constitutes a high-frequency circuitused in a transmitting/receiving unit provided in a portablecommunication terminal device or the like and adapted for processing ahigh-frequency signal. The circuit board device 1 has a structure inwhich a circuit part 2 and a semiconductor component 3 are electricallyconnected to and mounted on a major surface (hereinafter referred to asmounting surface) 4 a of a base board 4, for example, by a flip-chipbonding method using solder, and a filter element 5 is arranged betweenthe circuit part 2 and the base board 4.

[0042] The circuit part 2 is constructed as plural insulating layers 6made of a dielectric insulating material and plural patterned wiringlayers 7 are alternately stacked. Electric interlayer connection is madeby a via-hole 8 penetrating all the plural wiring layers 7 orpenetrating the upper and lower layers.

[0043] As will be later described in detail, the circuit part 2 isformed as the insulating layers 6 and the wiring layers 7 aresequentially stacked via a peeling layer 21 on a dummy board 20 having aflat major surface and are peeled from the dummy board 20 by the peelinglayer 21. Therefore, the structure of the circuit part 2 need not use acore board such as a glass board or an Si board. The dummy board 20 isreused when necessary.

[0044] In the circuit part 2, the insulating layers 6 are made of adielectric insulating material having low Tanδ at a low dielectricconstant, that is, having an excellent high-frequency characteristic.Specifically, a mixture of an organic material such as polyphenyleneether (PPE), bismaleidetriazine (BT-resin), polytetrafluoroethylene,polyimide, liquid crystal polymer (LCP), polynorbornene (PNB), phenolresin, or polyolefin resin, and an inorganic material such as ceramics,or a mixture of an organic material such as glass epoxy and an inorganicmaterial is used.

[0045] The wiring layers 7 forming the circuit part 2 are patternwirings formed by conductors made of, for example, copper or nickelplate with gold. The wiring layers 7 are formed, for example, by printprocessing or lithography processing.

[0046] The semiconductor component 3 is a functional circuit elementsuch as a semiconductor chip or an LSI (large-scale integrated circuit)chip and is mounted on the mounting surface 4 a of the base board 4, forexample, by a flip-chip bonding method using an element bump part 9.This semiconductor component 3 is mounted on the same plate as thecircuit part 2 mounted on the mounting surface 4 a of the base board 4,that is, parallel to the circuit part 2 on the base board 4.

[0047] The base board 4 has a structure in which plural insulatinglayers 10 and plural wiring layers 11 are alternately stacked, andinterlayer connection is made by a via-hole 12 penetrating all theplural wiring layers 11 or penetrating plural layers of them. The baseboard 4 has plural input/output terminal parts 13 on its front and backmajor surfaces. These input/output terminal parts 13 function, forexample, as connection terminals to an external power source, or asbases of electric connection parts for mounting the circuit part 2 andthe semiconductor component 3. The plural wiring layers 11 provided inthe base board 4 function as wirings for transmitting power, controlsignals and high-frequency signals supplied from the input/outputterminal parts 13 to the circuit part 2 and also function as ground(ground electrodes).

[0048] In base board 4, similarly to the circuit part 2, a dielectricinsulating material having low Tanδ at a low dielectric constant, thatis, having an excellent high-frequency characteristic, is used for theinsulating layers 10. Specifically, a mixture of an organic materialsuch as polyphenylene ether (PPE), bismaleidetriazine (BT-resin),polytetrafluoroethylene, polyimide, liquid crystal polymer (LCP),polynorbornene (PNB), phenol resin, or polyolefin resin, and aninorganic material such as ceramics, or a mixture of an organic materialsuch as glass epoxy and an inorganic material is used.

[0049] The wiring layers 11 provided in the base board 4, similar tothose in the circuit part 2, are pattern wirings formed by conductorsmade of, for example, copper or nickel plate with gold. The wiringlayers 11 are formed, for example, by print processing or lithographyprocessing. The base board 4 is manufactured through a typicalmultilayer wiring board manufacturing process.

[0050] In the filter element 5, a pair of resonator conductor patterns14 as a part of the wiring layers 7 are arranged to be exposed on asurface (hereinafter referred to as counter-surface) 2 a facing themounting surface 4 a of the base board 4 of the circuit part 2.Specifically, as the filter element 5, a BPF having a structure in whicha ground part 15 a provided in a part of the wiring layer 7 that issecond from the mounting surface 4 a of the base board 4 of the circuitpart 2 and a ground part 15 b provided in a part of the input/outputterminal parts 13 exposed on the mounting surface 4 a of the base board4 shield the pair of resonator conductor patterns 14 exposed on thecounter-surface 2 a of the circuit part 2, that is, a so-calledtri-plate structure, extends onto the circuit part 2 and the base board4. This filter element 5 may be one of a low-pass filter (LPF), ahigh-pass filter (HPF) and a band-pass filter (BPF).

[0051] In the circuit board device 1 of this structure, the circuit part2 is mounted on the mounting surface 4 a of the base board 4 so that thecircuit part 2 and base board 4 hold the pair of resonator conductorpatterns 14 of the filter element 5. The thick part where the circuitpart 2 is mounted on the base board 4 is a so-called thick plate region16, whereas the part where the circuit part 2 is not mounted on the baseboard 4 and that is thinner than the thick plate region 16 is a thinplate region 17.

[0052] In this circuit board device 1, the semiconductor component 3 ismounted parallel to the circuit part 2 on the mounting surface 4 a ofthe base board 4, that is, on the thin plate region 17. The thickness ofthe whole body including the semiconductor component 3 is made thin.

[0053] In the circuit board device 1, the resonator conductor patterns14 of the filter element 5 are arranged in an inner layer of the thickplate region 16, that is, between the circuit part 2 and the base board4, and the circuit part 2 and the base board 4 have the insulatinglayers 6 and 10 made of a dielectric insulating material over multiplelayers. Thus, the resonator conductor patterns 14 of the filter element5 can be covered with the sufficiently thick dielectric insulatingmaterial. Therefore, in the circuit board device 1, the thick dielectricinsulating material covers the pair of resonator conductor patterns 14of the filter element 5 and causes no deterioration in degree ofelectromagnetic coupling between the pair of resonator conductorpatterns 14, thereby preventing deterioration in filter characteristicdue to reduction in thickness of the dielectric insulating materialcovering the filter element 5.

[0054] In the circuit board device 1 to which the present invention isapplied, since the circuit part 2, which is relatively expensive, ismounted only in a necessary part instead of the entire mounting surface4 a of the base board 4, reduction in cost is realized.

[0055] In the circuit board device 1 to which the present invention isapplied, different dielectric insulating materials may be used for theinsulating layers 6 and the insulating layers 10, respectively. Forexample, in the circuit board device 1, if a dielectric insulatingmaterial having a high dielectric constant is used for the insulatinglayers 10 of the base board 4, miniaturization is realized by reductionin size of the resonator conductor patterns 14 of the filter element 5.If a dielectric insulating material having a low dielectric constant isused for the insulating layers 10, the loss of parasitic capacitance inthe filter element 5 can be reduced. In the circuit board device 1, if ahead-resistant dielectric insulating material is used for the insulatinglayers 6 of the circuit part 2, a passive element such as a capacitorelement, a register element, or an inductor element can be provided at apart of the wiring layers 7 of the circuit part 2.

[0056] A method for manufacturing the above-described circuit boarddevice 1 will now be described.

[0057] To manufacture the circuit board device 1, the circuit part 2 isformed first. When forming the circuit part 2, the dummy board 20 havingthe peeling layer 21 formed on its major surface 20 a is prepared, asshown in FIG. 8. For the dummy board 20, for example, a glass board, aquartz board or a silicon board having high heat resistance and a highlyflattened major surface is used. The peeling layer 21 includes a metalfilm 21 a of copper, aluminum or the like deposited to a thickness ofapproximately 1000 Å evenly over the entire major surface 20 a of thedummy board 20 by a sputtering method or a chemical vapor deposition(CVD) method, and a resin film 21 b of polyimide resin or the likedeposited to a thickness of approximately 1 to 2 μm over the entiremetal film 21 a by a spin coat method.

[0058] On the peeling layer 21, a first insulating layer 22 with an eventhickness is formed, as shown in FIG. 9. The first insulating layer 22is formed as a typically known dielectric insulating material asdescribed above in the conventional wiring board manufacturing processis applied onto the peeling layer 21, for example, by a spin coatmethod, a curtain coat method, a roll coat method, a dip coat method orthe like.

[0059] Next, in the first insulating layer 22, an aperture 22 a to bethe via-hole 8 is formed at a predetermined position by patternprocessing. In the case a photosensitive dielectric insulating materialis used for the first insulating layer 22, the aperture 22 a is formedby patterning processing using a photolithography technique. In the casea non-photosensitive dielectric insulating material is used for thefirst insulating layer 22, the aperture 22 a is formed by patterningprocessing based on dry etching or laser processing using a photoresistand a mask of aluminum or the like.

[0060] Next, in the first insulating layer 22, a wiring groove 23 isformed by etching processing, as shown in FIG. 10. An etching maskhaving an aperture corresponding to the wiring groove 23 is formed onthe first insulating layer 22, then dry etching using a reactive ionetching (RIE) method with oxygen plasma is performed in the regionexcept for the etching mask on first insulating layer 22, and then theetching mask is removed. Thus, the wiring groove 23 is formed.

[0061] Next, on the first insulating layer 22 having the wiring groove23 formed therein, a metal plating layer 24 is formed by metal platingprocessing, as shown in FIG. 11. The metal plating layer 24 is made of ahighly conductive metal such as copper. The metal plating processing maybe electroplating or electroless plating. The metal plating layer 24fills the entire major surface of the first insulating layer 22 wherethe wiring groove 23 is formed and the aperture 22 a, so that thethickest part of the metal plating layer 24 is thicker than the thickestpart of the first insulating layer 22. When the metal plating layer 24is formed by electroplating, the metal film 21 a of the peeling layer 21functions as a voltage applying electrode.

[0062] Next, as flattening processing of the metal plating layer 24 isperformed until the first insulating layer 22 is exposed, a first wiringlayer 25 embedded in the first insulating layer is formed on the majorsurface of the first insulating layer 22, as shown in FIG. 12. For theflattening processing, for example, a chemical-mechanical polishing(CMP) method is used in order to simultaneously polish the firstinsulating layer 22 and the metal plating layer 24, which are made ofdifferent materials. The CMP method enables polishing with materialselectivity so as to increase the polishing rate of the metal platinglayer 24 made of a metal such as copper, and realizes flattening of thepolished surface with high accuracy. At this point, the ground part 15 aarranged above the pair of resonator conductor patterns 14 of the filterelement 5 is provided at a part of the first wiring layer 25.

[0063] Next, a second insulating layer 26 and a second wiring layer 27are stacked on the first insulating layer 22 having the first wiringlayer 25 embedded therein, as shown in FIG. 13. These second insulatinglayer 26 and second wiring layer 27 are formed through a process similarto the process of forming the first insulating layer 22 and the firstwiring layer 25, using materials similar to those of the firstinsulating layer 22 and the first wiring layer 25. At this point, atcertain parts in the second wiring layer 27, the pair of resonatorconductor patterns 14 of the filter element S, a first shield part 28 aincluding plural via-holes as a shield surrounding the pair of resonatorconductor patterns 14, and the via-hole 8 for making interlayerconnection between the first wiring layer 25 and the second wiring layer27 are collectively formed.

[0064] In the second wiring layer 27, the pair of resonator conductorpatterns 14 are linearly formed and arranged substantially parallel toeach other so that they face each other in the direction of width, andfeeder parts 29 are formed protruding in the direction opposite to thefacing direction, from substantially central parts in the longitudinaldirection of the pair of resonator conductor patterns 14, as shown inFIG. 14. In the second wiring layer 27, the pair of resonator conductorpatterns 14 have a length that is substantially ¼ of the passingwavelength λ in the longitudinal direction. One end in the longitudinaldirection of each resonator conductor pattern 14 is connected to thefirst shield part 28 a and the other end is opened.

[0065] The surface of the second insulating layer 26 having the secondwiring layer 27 embedded therein is a surface flattened with highaccuracy by flattening processing, similarly to the first insulatinglayer 22. This surface becomes the counter-surface 2 a where the pair ofresonator conductor patterns 14 of the filter element 5 are exposed. Inthis embodiment, the wiring layers of the two-layer structure includingthe first wiring layer 25 and the second wiring layer 27 are used.However, the structure is not limited to this, and the process offorming the first insulating layer 22 and the first wiring layer 25 maybe repeated to form three or more wiring layers.

[0066] Next, in the counter-surface 2 a, a second shield part 28 b, forexample, made of solder, is formed on the exposed first shield part 28a, and a bump part 30 is similarly formed on the via-hole 8, as shown inFIG. 15. The second shield part 28 b is electrically connected with theground part 15 b that is exposed on the mounting surface 4 a of the baseboard 4 when the circuit part 2 is mounted on the base board 4, and thesecond shield part 28 b thus shields the pair of resonator conductorpatterns 14. The bump part 30 functions as an electric connection partin mounting the circuit part 2 on the base board 4 and may be formed asa nickel/copper plating layer, for example, using electroplating orelectroless plating.

[0067] The circuit part 2 in which the pair of resonator conductorpatterns 14 of the filter element 5 are arranged on the counter-surface2 a is thus formed. In the circuit part 2, the first insulating layer 22and the second insulating layer 26 constitute the above-described pluralinsulating layers 6, and the first wiring layer 25 and the second wiringlayer 27 constitute the above-described plural wiring layers 7.

[0068] Next, the dummy board 20 is removed together with the peelinglayer 21 from the circuit 2, as shown in FIG. 16. Specifically, thedummy board 20 and the peeling layer 21 together with the circuit part 2are impregnated with an acid solution such as hydrochloric acid ornitric acid. The acid solution slightly dissolves the metal film 21 a ofthe peeling layer 21 and enters between the metal film 21 a and theresin film 21 b. Thus, peeling between the metal film 21 a and the resinfilm 21 b proceeds. The dummy board 20 is removed in the state where theresin film 21 b remains on the other major surface 2 b on the side ofthe first insulating layer 22, of the circuit part 2. In this case, inthe circuit part 2, a protection layer for protecting the second wiringlayer 27 from the acid solution may be formed on the counter-surface 2 ain advance. The dummy board 20 may also be removed from the circuit part2, for example, by laser abrasion processing.

[0069] Next, the resin film 2 b remaining on the other major surface 2 bof the circuit part 2 is removed by a dry etching method, for example,using as oxygen plasma. This exposes the via-hole 8 on the other majorsurface 2 b of the circuit part 2. Since the major surface of the dummyboard 20 facing the other major surface 2 b is highly flattened, theother major surface 2 b of he circuit part 2 is highly flattened.

[0070] Next, the circuit part 2 is mounted on the base board 4 in such amanner that the pair of resonator conductor patterns 14 exposed on thecounter-surface 2 a and the ground part 15 b made up of a part of theinput/output terminal parts 13 exposed on the mounting surface 4 a ofthe base board 4 face each other, as shown in FIG. 17. The base board 4has the plural wiring layers 11 having the ground or the like within thelayers and the plural insulating layers 10. On the mounting surface 4 awhere the circuit part 2 is to be mounted, the input/output terminalparts 13 exposed from a protection layer 31 made of a resist or the likeare formed, and the ground part 15 b as a ground conductor to the pairof resonator conductor patterns 14 is formed at a position facing thefilter element 5, on the mounting surface 4 a.

[0071] As the circuit part 2 is electrically connected with theinput/output terminals 13 exposed on the mounting surface 4 a of thebase board 4 via the bump parts 30, the circuit part 2 is mounted on thebase board 4. Specifically, an under-filler 32 fills the space betweenthe circuit part 2 and the base board 4 where the bump parts 30 and theinput/output terminal parts 13 face each other. The bump parts 30 andthe input/output terminal parts 13 are heated, for example, by a solderreflow method, and thus joined together. The circuit part 2 is thusmounted on the mounting surface 4 a of the base board 4. At this point,the second shield part 28 b is electrically connected with the groundpart 15 b. The junction between the bump parts 30 and the input/outputterminal parts 13 is not limited to the solder reflow method. Forexample, contraction due to solidification of a resin material filledbetween the circuit part 2 and the base board 4 may be used forcompression bonding.

[0072] Thus, in the base board 4, the part where the circuit part 2 ismounted on the mounting surface 4 a is the thick plate region 16, andthe part where the circuit part 2 is not mounted on the mounting surface4 a, that is, the part where the mounting surface 4 a is exposed, is thethin plate region 17.

[0073] Next, on the mounting surface 4 a of the base board 4, thesemiconductor component 3 such as a semiconductor chip or an LSI chip ismounted in the thin plate region 17, as shown in FIG. 18. Thissemiconductor component 3 is electrically connected with the mountingsurface 4 a of the base board 4 via the element bump part 9 by aflip-chip bonding method. The mounting the semiconductor component 3 isnot limited to the flip-chip bonding method. For example, a phase downbonding method such as a tape automated bonding (TAB) method or a leadbeam bonding method may be used.

[0074] In this manner, the semiconductor component 3 is mounted on thesame plane as the circuit part 2 mounted on the mounting surface 4 a ofthe base board 4, that is, parallel to the circuit part 2 on the baseboard 4. The circuit board device 1 is thus manufactured.

[0075] In the method for manufacturing the circuit board device 1 asdescribed above, the semiconductor component 3 is mounted on themounting surface 4 a of the base board 4, that is, in the thin plateregion 17, so that the semiconductor component 3 becomes parallel to thecircuit part 2, and the semiconductor component 3 and the circuit part 2are mounted on the base board 4 in such a manner that the whole bodyincluding the semiconductor component 3 has a small thickness.Therefore, the circuit board device 1 having a reduced thickness isprovided.

[0076] In the method for manufacturing the circuit board device 1according to the present invention, the pair of resonator conductorpatterns 14 of the filter element 5 are formed in the inner layer of thethick plate region 16, that is, between the circuit part 2 and the baseboard 4, and the plural insulating layer 6 and 10 made of a dielectricinsulating material are arranged above and below the filter element 5.Therefore, the pair of resonator conductor patterns 14 of the filterelement 5 can be covered with the sufficiently thick dielectricinsulating material, and the circuit board device 1 is provided in whichdeterioration in filter characteristic due to the thinning of thedielectric insulating material covering the pair of resonator conductorpatterns 14 is prevented.

[0077] In this method for manufacturing the circuit board device 1, thecircuit part 2, which is relatively expensive, is mounted only on anecessary part instead of the entire mounting surface 4 a of the baseboard 4. Therefore, the circuit board device 1 of lower cost isprovided.

[0078] In the above-described embodiment, the circuit board device 1having the circuit part 2 and the semiconductor component 3 mountedparallel to each other on the mounting surface 4 a of the base board 4is described. However, the present invention is not limited to this andcan also be applied to, for example, a circuit board device 40 having astructure as shown in FIG. 19. In FIG. 19, the same structural parts asthose of the above-described circuit board device 1 are denoted by thesame numerals and will not be described further in detail.

[0079] In this circuit board device 40, a thick semiconductor component41 that is thicker than the circuit part 2 and a thin semiconductorcomponent 42 that is thinner than the circuit part 2 are mounted. Inthis case, for example, the thick semiconductor component 41 can bemounted in the thin plate region 17 and the thin semiconductor component42 can be mounted on the other major surface 2 b of the circuit part 2.Thus, in the circuit board device 40, the thickness of the whole bodycan be reduced to realize reduction in thickness even when a thick andlarge semiconductor component is mounted.

[0080] In this embodiment, the filter element 5 of the tri-platestructure is arranged in the circuit board device 1, as described above.However, the filter element is not limited to this structure. Forexample, a filter element of a flat structure may also be used, and acoupler element, an antenna element, a capacitor element, a registerelement or an inductor element based on a lumped constant design, aregister element may be used instead of the filter element.

[0081] While the invention has been described in accordance with acertain preferred embodiment thereof illustrated in the accompanyingdrawings and described in the above description in detail, it should beunderstood by those ordinarily skilled in the art that the invention isnot limited to the embodiment, but various modifications, alternativeconstructions or equivalents can be implemented without departing fromthe scope and spirit of the present invention as set forth and definedby the appended claims.

Industrial Applicability

[0082] As described above, according to the present invention, thefilter element is arranged between the base board and the circuit parton the major surface of the base board and the semiconductor componentis thus mounted immediately on the second region thinner than the thickfirst region. Therefore, the thickness of the whole circuit board deviceis reduced and miniaturization is realized.

[0083] Moreover, according to the present invention, the filter elementis arranged inside the thick first region, that is, between the baseboard and the circuit part having the dielectric insulating layers, andthe filter element can be covered with the sufficiently thick dielectricinsulating layers. Therefore, the circuit board device is provided inwhich deterioration in filter characteristic due to the thinning of thedielectric insulating layers covering the filter element is prevented.

[0084] Furthermore, according to the present invention, the circuitpart, which is relatively expensive, is mounted only on the necessarypart instead of the entire surface of the base board. Therefore,reduction in cost of the circuit board device is realized.

1. A circuit board device comprising: a base board having an insulatinglayer made of a dielectric insulating material; a circuit part includinga wiring layer and a dielectric insulating layer and mounted on a majorsurface of the base board; a filter element arranged between the baseboard and the circuit part; and a semiconductor component mounted on thesame plane as the circuit part mounted on the major surface of the baseboard; the semiconductor component being mounted on a second regionhaving a thickness smaller than that of a first region having a largethickness as the filter element is arranged between the base board andthe circuit part on the major surface of the base board.
 2. The circuitboard device as claimed in claim 1, wherein the filter element isarranged on the major surface of the base board or a major surface ofthe circuit part facing the base board.
 3. The circuit board device asclaimed in claim 1, wherein the filter element is one of a band-passfilter, a band-stop filter, a low-pass filter, a high-pass filter, anantenna, and a directional coupler.
 4. A method for manufacturing acircuit board device comprising: a board forming step of forming a baseboard having an insulating layer made of a dielectric insulatingmaterial; a circuit part forming step of forming a circuit partincluding a wiring layer and a dielectric insulating layer; an elementforming step of forming a filter element on a major surface of the baseboard or a major surface of the circuit part; a circuit part mountingstep of mounting the circuit part on the major surface of the base boardso that the filter element is arranged between the base board and thecircuit part; and a semiconductor mounting step of mounting asemiconductor component on the same plane as the circuit part mounted onthe major surface of the base board; wherein at the semiconductormounting step, the semiconductor component is mounted on a second regionhaving a thickness smaller than that of a first region having a largethickness as the filter element is arranged between the base board andthe circuit part on the major surface of the base board.
 5. The methodfor manufacturing a circuit board device as claimed in claim 4, whereinat the element forming step, the filter element is formed as one of aband-pass filter, a band-stop filter, a low-pass filter, a high-passfilter, an antenna, and a direction coupler.